Add type annotation for goog.ui.Zippy.Events
Add type annotation for goog.ui.Zippy.Events

RELNOTES: Fix js_lib compile error

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=223564616

lucidsoftware/closure-library,google/closure-library,lucidsoftware/closure-library,google/closure-library,lucidsoftware/closure-library,google/closure-library,google/closure-library,google/closure-library,lucidsoftware/closure-library